Display screen or portion thereof with an animated graphical user interface



FIG. 1 is a front view of a first embodiment of a display screen or portion thereof with an animated graphical user interface, showing a first image of our new design;

FIG. 2 is a second image thereof;

FIG. 3 is a third image thereof;

FIG. 4 is a fourth image thereof;

FIG. 5 is a front view of a second embodiment of a display screen or portion thereof with an animated graphical user interface, showing a first image of our new design;

FIG. 6 is a second image thereof;

FIG. 7 is a third image thereof; and,

FIG. 8 is a fourth image thereof.

The appearance of the transitional image sequentially transitions between the images shown in FIGS. 1-4, FIGS. 4-1, FIGS. 5-8 and FIGS. 8-5. The process or period in which one image transitions to another image forms no part of the claimed design.

The outermost dash-dash broken line depicting the display screen or portion thereof, and all other dash-dash broken lines depicting portions of the graphical user interface, show portions of the article and form no part of the claimed design. The dot-dash broken lines show boundaries of the claim, and form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with an animated graphical user interface, as shown and described. 